Necticut



Patented May 3, 1927.

"U NIT ED S TATE S PATENT OFFICE.

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Ho Drawing.

' This invention relatesto a process for preparmg a reaction product of acetaldehyde and aniline.

Its principal ob ect is-to provide. a simple,

' efiicient process for manufacturing this maand that within certainlimits of acidity a high yield of the desired product is obtained, and that outside of these limits either a greatly lower ield is obtained or .a yield ot a product with other qualities is secured. v

-The invention accordingly consists in a process for preparing a reaction product of acetaldehyde and aniline which com rises combining acetaldehyde with aniline 1n the presence of a solution having hydrogen ion concentration oflXllT? to 2.5)(101 In one manner' of carryin out the invention, 1500 parts by weight 0 an aqueous solution containing 121 parts by weight of anhydrous sodium acetate, and 9.2 parts by weight of glacial acetic acid (or equivalent amount of commercial acid) are prepared. and by this solution 1760 partsby weight of acetaldehyde are absorbed while the solution is maintained at substantially room temperature, 70 F. approximately. It will be noted that the amount, of acetaldehyde given, 1760 parts by weight is the amount absorbed, not the amount run into the solution. This solution is preferably kept over night in a closed vessel. Thereupon 1500 parts by weight of aniline are added to the vigorously stirred solution in the course of two hours. The temperature ofthe mixture is preferably notallowed to' rise above LO- C. Any escaping acetaldehyde is caught and returned by a reflux condenser. 50 After the aniline is all added the mixture is maintained at 40-50" C. with continuous stirring for three hours and then allowed to stand over. night. Thereupon the supernal' taut liquid is siphoned off and the mixture Application filed ltay fllfi, 192$..seria1 No. 641,764.

is distilled preferably in vacuo at 140 C. for not more than three hours. Ordinary pressure may be employed if desired. I

The water solution of sodium acetate and acetic acid produces a solution having a hydrogen ion concentration of approximate-' ly 25x10. Substantially equally good results may be obtained where other materials than sodium acetate and acetic acid are employed, and where the hydrogen ITOIIGOIP/ centration lies between 2.5 10-*' and 2.5 10-f. Good results ma also be obtained where the range of hy rogen ion conccntration is from 1X10 .to 1x10 A greater hydrogen ion concentration than 1X10 produces a reaction product which is a weak accelerator. A hydrogen ion concentration less thaii 1X10 produces a relatively poor yield. I

It will be understood of course that'ac'et-- aldehyde employed above in the preferred example may be employed as a gas as such or may be produced either in the presence of aniline or otherwise as desired.

The reaction between acetaldehyde and aniline is best carried on at temperatures from 3592 .C. It has been found that prolonged heating has a bad effect upon 7 the condensation product. It requires long heating to remove any large amount of aniline which has not reacted with the acetaldehyde, therefore it is desirable to cause all y the aniline to react first by adding an,excess of acetaldehyde and second by stirring the reaction mixture under, a reflux condenser for some time so as to insure a complete reaction. As indicated in the preferred example an excess of acetaldehyde over that required by the proportion of 2 molecules of acetaldehyde and 1molecule of aniline is employed. If aniline remains in the reaction product the accelerating property of the'product remains about the same as if no aniline were present. However such product has the objection that it possesses the objectionable odor of aniline and also the toxic properties thereof.

-.The reaction product resulting from the abqve procedure gives the following results .when used in the vulcanization of rubber:

ing in the usual manner and the resulting is obtained. A

mixture vuloani'z ed in 'a;.1'1r1oldwith steam at 40""lbs."pressure for60 minutes a rubber having an average tensile strength of approximately; 28(lQ 3QQO lbs. per square inch On the other thereaction product of acct-aldehyde and aniline prepared in the presence of a water solution having ahydro gen ion concentration of greaterthan 1 10' -for hydrochloric acid giving a hydrogen ion concentration of approximately 1X10' produces a reaction product which'has' practically noaccelerating properties; Again a reaction product-prepared in the presence ofa water solution having a hydrogen n con- "ccntrationlof less than 1X10; for example inthe presence'of sodium borate producing a hydrogen ion concentration of 5.7 )(10' approximately produces a yield about asgreat as'wo'uld be obtained under the op- "timurn conditions given above. I Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1.A process for pre aring the reaction product of acetaldeh e which comprises combiningacetaldehy a with aniline in the presence of a water solution to' which is imexample in the presence of, '1X10' to 2.5 l0' which is imparted a hydrogen ion-ooncentration of 1X10 to 2.5X10'.

3. A process for re arin'g the reaction product of acetalde (it which comprises combining acetaldehyde with aniline in the presence of a water solution to which is imparted a hydrogen ion concentration of at a temperature of 35- 92 C.

4:. A process for preparing the reaction product of acetaldehyde which comprises combining acetaldehyde in an amount slightly'in excess of 2 molecules with aniline in an amount "of a proximately 1 molecule in the presence 0 a water solution to which is imparted a hydrogen ion concentration of 2.5X10" to 2.5X10', maintaining the temperature at, 4050 C.

5. A process for preparing the reaction 1 line in an amount ofapproximately 1 molecule in" the presence of a water solution to product of acetaldehyde which comprises preparing 1500 parts by weightof an aqueous solution containing 12.1 parts of anhydrous sodium acetate and 9.2 parts of glacial acetic acid, absorbin thereby 1760 parts by weight of acetal ehyde, adding 1500 parts of aniline to the solution, maintainin the temperature at 40-50 C.', and distilling the resulting product at140 C. approximately to ridthe product of aniline.

Si ned at New York, count and State of ew York, this,23rd day 0 May, 1923.

SIDNEY M. CADWELL.

in an amount 

